Climate-catchment-soil control on hydrological droughts in peninsular India.

Area of Science:

• Hydrology
• Soil Science
• Climate Science

Background:

• Land surface models often overlook detailed soil characteristics when assessing drought attributes like growth, duration, and recovery.
• Understanding the interplay between climate, catchment, and soil properties is crucial for accurate hydrological drought analysis.

Purpose of the Study:

• To investigate the influence of climate-catchment-soil interactions on hydrological drought characteristics in peninsular India.
• To quantify the contribution of terrain and soil properties to drought variability and resilience.

Main Methods:

• Utilized national-scale digital soil maps and daily observed streamflow data from 98 sites in tropical rain-dominated catchments.
• Assessed the climate-catchment-soil nexus to determine drivers of drought attributes.

Main Results:

• Climate-catchment-soil properties collectively influence hydrological drought attributes, explaining 14-70% of variability.
• Terrain features primarily drive drought growth (approx. 50% variability), while soil attributes significantly impact drought duration (approx. 71.5% variability).
• Soil organic carbon (SOC) stock demonstrates a capacity to resist drought propagation, even in low-carbon soils.

Conclusions:

• Soil and climatic factors jointly govern drought resilience and termination rates.
• Temperature and soil moisture are key climatic factors controlling streamflow drought resilience.
• Future drought propagation models must incorporate feedback mechanisms among climate, soil, and topographical properties at the catchment scale.